Perhaps the first photo of a noctilucent cloud taken from the ground, this 'night- shining cloud' was caught on film over Budapest this year.

In recent years, noctilucent (night-shining) clouds, which form at very high altitudes over the poles in the summer months, have been appearing  more frequently at lower latitudes and growing brighter, possibly as a result of climate change.

NASA's new Aeronomy of Ice in the Mesosphere (AIM) satellite is dedicated to observing these clouds, which are high enough they continue reflecting sunlight well after the sun has set below the horizon.

The AIM satellite has provided scientists with a global-scale view of the cloud formations over the course of the entire 2007 Northern Hemisphere summer, yielding unexpected results. They observed an increase in both hemispheres at lower latitudes and suspect it may be linked to climate change. While increased carbon dioxide levels warm the lower atmosphere, they have a cooling effect on the level of the upper atmosphere where noctilucent clouds form.

  Mission scientists at meeting of the American Geophysical Union on December 10^th said   AIM's measurements showed that these unusual clouds varied more in structure than expected.   They believe this signifies the extreme sensitivity of the environment where the clouds form as water vapor condensing around dust particles  fifty miles above the earth (80km).   At that altitude, temperatures dip to -235 degrees Fahrenheit and the air is 100,000 times drier than the air in the Sahara desert.

The AIM mission also found that this mesospheric ice seems to occur in one continuous layer above Earth's surface.